Active and Passive Electronic Components The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. The Design and Thermal Reliability Analysis of a High-Efficiency K-Band MMIC Medium-Power Amplifier with Multiharmonic Matching Thu, 19 May 2016 12:59:35 +0000 A new high-efficiency K-band MMIC medium-power amplifier (PA) is designed with multiharmonic matching using GaAs pHEMT process technology. It has an operation frequency centered at 26 GHz with a bandwidth of 2 GHz. A 20 dBm 1 dB-compression-point output power and 40% efficiency are achieved. A novel thermal reliability analysis method based on ICEPAK is proposed also to evaluate its thermal characteristic. The test result by using a QFI InfraScope™ infrared imaging system is compared with the simulation result. It agrees well with an accuracy within ±1°C differences, which reflects the advantages of the thermal analysis method with respect to accuracy and convenience for use. Y. Shang, H. Xu, J. Mo, Z. Wang, X. Xu, Z. Tu, X. Zhang, H. Zheng, W. Chen, and F. Yu Copyright © 2016 Y. Shang et al. All rights reserved. A Survey on the Modeling of Magnetic Tunnel Junctions for Circuit Simulation Wed, 18 May 2016 07:12:22 +0000 Spin-transfer torque-based magnetoresistive random access memory (STT-MRAM) is a promising candidate for universal memory that may replace traditional memory forms. It is expected to provide high-speed operation, scalability, low-power dissipation, and high endurance. MRAM switching technology has evolved from the field-induced magnetic switching (FIMS) technique to the spin-transfer torque (STT) switching technique. Additionally, material technology that induces perpendicular magnetic anisotropy (PMA) facilitates low-power operation through the reduction of the switching current density. In this paper, the modeling of magnetic tunnel junctions (MTJs) is reviewed. Modeling methods and models of MTJ characteristics are classified into two groups, macromodels and behavioral models, and the most important characteristics of MTJs, the voltage-dependent MTJ resistance and the switching behavior, are compared. To represent the voltage dependency of MTJ resistance, some models are based on physical mechanisms, such as Landau-Lifshitz-Gilbert (LLG) equation or voltage-dependent conductance. Some behavioral models are constructed by adding fitting parameters or introducing new physical parameters to represent the complex switching behavior of an MTJ over a wide range of input current conditions. Other models that are not based on physical mechanisms are implemented by simply fitting to experimental data. Hyein Lim, Seungjun Lee, and Hyungsoon Shin Copyright © 2016 Hyein Lim et al. All rights reserved. Corrigendum to “Analysis of the Coupling Coefficient in Inductive Energy Transfer Systems” Tue, 10 May 2016 09:17:26 +0000 Rafael Mendes Duarte and Gordana Klaric Felic Copyright © 2016 Rafael Mendes Duarte and Gordana Klaric Felic. All rights reserved. Design of Wide-Band Bandpass Filter Using Composite Right/Left-Handed Transmission Line Structure Mon, 11 Apr 2016 13:33:19 +0000 A wide-band microstrip bandpass filter (BPF) based on the improved composite right/left-handed transmission line (CRLH-TL) structure is presented in this paper. Compared to the traditional CRLH-TL with via hole, the improved one is an all-planar structure, which owns the advantage of fabrication and loss. The equivalent lossless LC circuit model of the proposed structure is established. EM software Sonnet is adopted to design the wide-band filter with bandwidth of 1.4 GHz (from 1.9 GHz to 3.3 GHz). The circuit occupies only 20.6 × 12.8 mm2. Finally, the fabrication and measurement are implemented. A good agreement between simulation and measured results verifies the validity of the design methodology. Baoping Ren, Haiwen Liu, Xuehui Guan, Pin Wen, Xiang Xiao, and Zhewang Ma Copyright © 2016 Baoping Ren et al. All rights reserved. Design and Simulation of a 6-Bit Successive-Approximation ADC Using Modeled Organic Thin-Film Transistors Tue, 15 Mar 2016 09:49:23 +0000 We have demonstrated a method for using proper models of pentacene P-channel and fullerene N-channel thin-film transistors (TFTs) in order to design and simulate organic integrated circuits. Initially, the transistors were fabricated, and we measured their main physical and electrical parameters. Then, these organic TFTs (OTFTs) were modeled with support of an organic process design kit (OPDK) added in Cadence. The key specifications of the modeled elements were extracted from measured data, whereas the fitting ones were elected to replicate experimental curves. The simulating process proves that frequency responses of the TFTs cover all biosignal frequency ranges; hence, it is reasonable to deploy the elements to design integrated circuits used in biomedical applications. Complying with complementary rules, the organic circuits work properly, including logic gates, flip-flops, comparators, and analog-to-digital converters (ADCs) as well. The proposed successive-approximation-register (SAR) ADC consumes a power of 883.7 µW and achieves an ENOB of 5.05 bits, a SNR of 32.17 dB at a supply voltage of 10 V, and a sampling frequency of about 2 KHz. Huyen Thanh Pham, Thang Vu Nguyen, Loan Pham-Nguyen, Heisuke Sakai, and Toan Thanh Dao Copyright © 2016 Huyen Thanh Pham et al. All rights reserved. Bus Implementation Using New Low Power PFSCL Tristate Buffers Mon, 29 Feb 2016 12:01:38 +0000 This paper proposes new positive feedback source coupled logic (PFSCL) tristate buffers suited to bus applications. The proposed buffers use switch to attain high impedance state and modify the load or the current source section. An interesting consequence of this is overall reduction in the power consumption. The proposed tristate buffers consume half the power compared to the available switch based counterpart. The issues with available PFSCL tristate buffers based bus implementation are identified and benefits of employing the proposed tristate buffer topologies are put forward. SPICE simulation results using TSMC 180 nm CMOS technology parameters are included to support the theoretical formulations. The performance of proposed tristate buffer topologies is examined on the basis of propagation delay, output enable time, and power consumption. It is found that one of the proposed tristate buffer topology outperforms the others in terms of all the performance parameters. An examination of behavior of available and the proposed PFSCL tristate buffer topologies under parameter variations and mismatch shows a maximum variation of 14%. Neeta Pandey, Bharat Choudhary, Kirti Gupta, and Ankit Mittal Copyright © 2016 Neeta Pandey et al. All rights reserved. Energy-Aware Low-Power CMOS LNA with Process-Variations Management Thu, 18 Feb 2016 06:51:48 +0000 A reconfigurable low-noise amplifier (LNA) with digitally controllable gain and power consumption is presented. This architecture allows increasing power consumption only when required, that is, to improve LNA’s radiofrequency performance at extreme communication-channel conditions and/or to counteract the effect of process, voltage, and temperature variations. The proposed design leads to significant power saving when a relaxed operation is acceptable. The LNA is implemented in a 130 nm 1.2 V CMOS technology for a 2.4 GHz IEEE-802.15.4 application. Simulated LNA performance (taking into account the worst cases under process variations) is comparable to recently published works. Jorge Luis González, Robson Luiz Moreno, Juan Carlos Cruz, and Diego Vázquez Copyright © 2016 Jorge Luis González et al. All rights reserved. A Novel Inverter Topology for Single-Phase Transformerless PV System Wed, 13 Jan 2016 14:02:57 +0000 Transformerless photovoltaic (PV) power system is very promising due to its low cost, small size, and high efficiency. One of its most important issues is how to prevent the common mode leakage current. In order to solve the problem, a new inverter is proposed in this paper. The system common mode model is established, and the four operation modes of the inverter are analyzed. It reveals that the common mode voltage can be kept constant, and consequently the leakage current can be suppressed. Finally, the experimental tests are conducted. The experimental results verify the effectiveness of the proposed solution. Haiyan Cao Copyright © 2016 Haiyan Cao. All rights reserved. Anomalous DIBL Effect in Fully Depleted SOI MOSFETs Using Nanoscale Gate-Recessed Channel Process Wed, 28 Oct 2015 09:41:36 +0000 Nanoscale Gate-Recessed Channel (GRC) Fully Depleted- (FD-) SOI MOSFET device with a silicon channel thickness () as low as 2.2 nm was first tested at room temperature for functionality check and then tested at low temperature (77 K) for characterizations. In spite of its FD-SOI nanoscale thickness and long channel feature, the device has surprisingly exhibited a Drain-Induced Barrier Lowering (DIBL) effect at RT. However, this effect was suppressed at 77 K. If the apparition of such anomalous effect can be explained by a parasitic short channel transistor located at the edges of the channel, its suppression is explained by the decrease of the potential barrier between the drain and the channel when lowering the temperature. Avi Karsenty and Avraham Chelly Copyright © 2015 Avi Karsenty and Avraham Chelly. All rights reserved. A High Efficiency Li-Ion Battery LDO-Based Charger for Portable Application Mon, 07 Sep 2015 09:38:55 +0000 This paper presents a high efficiency Li-ion battery LDO-based charger IC which adopted a three-mode control: trickle constant current, fast constant current, and constant voltage modes. The criteria of the proposed Li-ion battery charger, including high accuracy, high efficiency, and low size area, are of high importance. The simulation results provide the trickle current of 116 mA, maximum charging current of 448 mA, and charging voltage of 4.21 V at the power supply of 4.8–5 V, using 0.18 μm CMOS technology. Youssef Ziadi and Hassan Qjidaa Copyright © 2015 Youssef Ziadi and Hassan Qjidaa. All rights reserved. Thermomechanical Behaviour of a PWB by Speckle Interferometry Technique Tue, 18 Aug 2015 09:50:21 +0000 The speckle interferometry technique has been used in this work in order to determine the thermomechanical behaviour of Printed Wiring Board (PWB) (circuits) of a radio integrated with tape player and speakers. A preliminary experiment of such technique has been carried out on a single electronic component (silicon transistor), during the thermal transient and at the steady state. The thermal deformation and stresses on PWB have been obtained through related experimental analyses on both cases. The results showed a very good applicability of speckle technique on the irregular object surface as PWB. Bartolomeo Trentadue and Giuseppe Illuzzi Copyright © 2015 Bartolomeo Trentadue and Giuseppe Illuzzi. All rights reserved. A Very Compact and Sharp Roll-Off Low-Pass Filter with Four Transmission Zeros Tue, 11 Aug 2015 05:48:49 +0000 A novel structure with sharp roll-off, wide stopband, and very compact size is presented in this paper. By combining a capacitor-embedded transmission line ring and two shunt open stubs, this structure exhibits a high-performance three-pole low-pass filter (LPF) response with four generated transmission zeros. With the help of these four transmission zeros, the proposed LPF achieves improved roll-off rate, extended stopband, and significantly very compact size. To verify the feasibility of the proposed structure, a prototype LPF having the cut-off frequency at 0.63 GHz is designed, fabricated, and measured as an illustrative example. Final result shows that a roll-off rate of 109.3 dB/GHz along with a relative stopband bandwidth of 114.6% can be obtained. Moreover, the filter dimensions are as small as 15.7 mm × 26.9 mm, that is, , where is the guided wavelength at the cut-off frequency. The filter structure is simple and easy to fabricate as well. Yang Xiao and Lin Li Copyright © 2015 Yang Xiao and Lin Li. All rights reserved. Analytical Model of Random Variation in Drain Current of FGMOSFET Wed, 15 Jul 2015 08:35:27 +0000 The analytical model of random variation in drain current of the Floating Gate MOSFET (FGMOSFET) has been proposed in this research. The model is composed of two parts for triode and saturation region of operation where the process induced device level random variations of each region and their statistical correlations have been taken into account. The nonlinearity of floating gate voltage and dependency on drain voltage of the coupling factors of FGMOSFET have also been considered. The model has been found to be very accurate since it can accurately fit the SPICE BSIM3v3 based reference obtained by using Monte-Carlo SPICE simulation and FGMOSFET simulation technique with SPICE. It can fit the BSIM4 based reference if desired by using the optimally extracted parameters. By using the proposed model, the variability analysis of FGMOSFET and the analytical modeling of the variation in the circuit level parameter of any FGMOSFET based circuit can be performed. So, this model has been found to be an efficient tool for the variability aware analysis and design of FGMOSFET based circuit. Rawid Banchuin Copyright © 2015 Rawid Banchuin. All rights reserved. Design of a Novel High Power V-Band Helix-Folded Waveguide Cascaded Traveling Wave Tube Amplifier Mon, 01 Jun 2015 09:47:15 +0000 A design of a V-band Helix-Folded Waveguide (H-FWG) cascaded traveling wave tube (TWT) is presented. In this cascaded structure, a digitized nonlinear theory model is put forward first to simulate these two types of the tubes by common process. Then, an initial design principle is proposed, which can design these two different kinds of tubes universally. Using this principle, a high-gain helix TWT is carefully designed as a first stage amplifier followed by a FWG TWT to obtain high power. Simulations predict that a peak power of 800 W with saturated gain of 60 dB from 55 GHz to 60 GHz can be achieved. Tianxiang Zhuge and Yulu Hu Copyright © 2015 Tianxiang Zhuge and Yulu Hu. All rights reserved. Usage and Limitation of Standard Mobility Models for TCAD Simulation of Nanoscaled FD-SOI MOSFETs Tue, 26 May 2015 12:17:42 +0000 TCAD tools have been largely improved in the last decades in order to support both process and device complementary simulations which are usually based on continuously developed models following the technology progress. In this paper, we compare between experimental and TCAD simulated results of two kinds of nanoscale devices: ultrathin body (UTB) and nanoscale Body (NSB) SOI-MOSFET devices, sharing the same W/L ratio but having a channel thickness ratio of 10 : 1 (46 nm and 4.6 nm, resp.). The experimental transfer I-V characteristics were found to be surprisingly different by several orders of magnitude. We analyzed this result by considering the severe mobility degradation and the influence of a large gate voltage dependent series resistance (). TCAD tools do not usually consider to be either channel thickness or gate voltage dependent. After observing a clear discrepancy between the mobility values extracted from our measurements and those modeled by the available TCAD models, we propose a new semiempirical approach to model the transfer characteristics. A. Ciprut, A. Chelly, and A. Karsenty Copyright © 2015 A. Ciprut et al. All rights reserved. Control for the Three-Phase Four-Wire Four-Leg APF Based on SVPWM and Average Current Method Mon, 16 Mar 2015 13:12:29 +0000 A novel control method is proposed for the three-phase four-wire four-leg active power filter (APF) to realize the accurate and real-time compensation of harmonic of power system, which combines space vector pulse width modulation (SVPWM) with triangle modulation strategy. Firstly, the basic principle of the APF is briefly described. Then the harmonic and reactive currents are derived by the instantaneous reactive power theory. Finally simulation and experiment are built to verify the validity and effectiveness of the proposed method. The simulation results show that the response time for compensation is about 0.025 sec and the total harmonic distortion (THD) of the source current of phase is reduced from 33.38% before compensation to 3.05% with APF. Xiangshun Li and Jianghua Lu Copyright © 2015 Xiangshun Li and Jianghua Lu. All rights reserved. Trigger Pulse Generator Using Proposed Buffered Delay Model and Its Application Sun, 18 Jan 2015 07:32:16 +0000 This paper proposes a circuit capable of incorporating buffered delays in the order of picoseconds. To study our proposed circuit in the profound way, we have also explored our proposed circuit using emerging technologies such as FinFET and CNFET. Comparisons between these technologies have been made in terms of different parameters such as duration of incorporated delays (pulse width) and its variability with supply voltages. Further, this paper also proposes a trigger pulse generator by utilizing proposed buffered delay circuit as its basic element. Parametric results obtained for the proposed trigger pulse generator match different application specific requirements. These applications are also mentioned in this paper. The proposed trigger pulse generator requires very low supply voltage (700 mV) and also proves its effectiveness in terms of tunability of pulse width of the generated pulses. The modeling of the circuit has been done using Verilog and the simulation results are extensively verified using SPICE. Amit Krishna Dwivedi, Kumar Abhijeet Urma, and Aminul Islam Copyright © 2015 Amit Krishna Dwivedi et al. All rights reserved. On the Evaluation of Gate Dielectrics for 4H-SiC Based Power MOSFETs Thu, 01 Jan 2015 12:33:16 +0000 This work deals with the assessment of gate dielectric for 4H-SiC MOSFETs using technology based two-dimensional numerical computer simulations. Results are studied for variety of gate dielectric candidates with varying thicknesses using well-known Fowler-Nordheim tunneling model. Compared to conventional SiO2 as a gate dielectric for 4H-SiC MOSFETs, high- gate dielectric such as HfO2 reduces significantly the amount of electric field in the gate dielectric with equal gate dielectric thickness and hence the overall gate current density. High- gate dielectric further reduces the shift in the threshold voltage with varying dielectric thicknesses, thus leading to better process margin and stable device operating behavior. For fixed dielectric thickness, a total shift in the threshold voltage of about 2.5 V has been observed with increasing dielectric constant from SiO2 () to HfO2 (). This further results in higher transconductance of the device with the increase of the dielectric constant from SiO2 to HfO2. Furthermore, 4H-SiC MOSFETs are found to be more sensitive to the shift in the threshold voltage with conventional SiO2 as gate dielectric than high-k dielectric with the presence of interface state charge density that is typically observed at the interface of dielectric and 4H-SiC MOS surface. Muhammad Nawaz Copyright © 2015 Muhammad Nawaz. All rights reserved. Investigation of the Low-Temperature Behavior of FD-SOI MOSFETs in the Saturation Regime Using and Functions Mon, 15 Dec 2014 09:07:57 +0000 The saturation regime of two types of fully depleted (FD) SOI MOSFET devices was studied. Ultrathin body (UTB) and gate recessed channel (GRC) devices were fabricated simultaneously on the same silicon wafer through a selective “gate recessed” process. They share the same W/L ratio but have a channel film thickness of 46 nm and 2.2 nm, respectively. Their standard characteristics ( and ) of the devices were measured at room temperature before cooling down to 77 K. Surprisingly, their respective temperature dependence is found to be opposite. In this paper, we focus our comparative analysis on the devices' conduction using a Y-function applied to the saturation domain. The influence of the temperature in this domain is presented for the first time. We point out the limits of the Y-function analysis and show that a new function called Z can be used to extract the series resistance in the saturation regime. A. Karsenty and A. Chelly Copyright © 2014 A. Karsenty and A. Chelly. All rights reserved. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors Wed, 19 Nov 2014 09:43:32 +0000 The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC-) graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP) stressing can be used to trim the polymer thick film resistors either upwards or downwards. Busi Rambabu and Y. Srinivasa Rao Copyright © 2014 Busi Rambabu and Y. Srinivasa Rao. All rights reserved. Realization of DVCCTA Based Versatile Modulator Mon, 27 Oct 2014 09:02:02 +0000 A Differential Voltage Current Conveyor Transconductance Amplifier (DVCCTA) based versatile modulator is proposed which can work as an amplitude modulator, frequency modulator, delta modulator, and sigma delta modulator. The modulator operational scheme uses pulse generator as a core and its output is used as carrier signal. A DVCCTA based pulse generator is proposed first and subsequently configured as different modulators. Compact realization is the key feature of the proposed circuit as it uses two DVCCTA; a grounded resistor and a grounded capacitor hence are appropriate for IC realization. The functionality of the proposed circuit is verified through SPICE simulations using TSMC 0.25 μm CMOS process model parameters. The performance parameters such as power dissipation and noise for various modulator schemes are also obtained. Neeta Pandey, Rajeshwari Pandey, Aseem Sayal, and Manan Tripathi Copyright © 2014 Neeta Pandey et al. All rights reserved. Reconfigurable Mixed Mode Universal Filter Mon, 20 Oct 2014 08:25:05 +0000 This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types) at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters. Neelofer Afzal and Devesh Singh Copyright © 2014 Neelofer Afzal and Devesh Singh. All rights reserved. Sinusoidal Generator with π/4-Shifted Four/Eight Voltage Outputs Employing Four Grounded Components and Two/Six Active Elements Thu, 28 Aug 2014 05:21:00 +0000 This paper presents a new circuit proposal for multiphase sine-wave generation, employing two active elements and four grounded passive elements. The proposed oscillator provides four 45° phase-shifted voltage outputs. Incorporation of additional inverters for generation of eight-phase outputs is further shown. Simultaneous current outputs can also be generated with additional output stages. The compact circuit structure is studied for nonideal and parasitic effects and simulation results are given, which are in good agreement with the theory. The utility of the proposal for π/4-QPSK generation is explored as an interesting application example with supporting results. Sudhanshu Maheshwari Copyright © 2014 Sudhanshu Maheshwari. All rights reserved. Implementation of Power Efficient Flash Analogue-to-Digital Converter Thu, 14 Aug 2014 11:36:04 +0000 An efficient low power high speed 5-bit 5-GS/s flash analogue-to-digital converter (ADC) is proposed in this paper. The designing of a thermometer code to binary code is one of the exacting issues of low power flash ADC. The embodiment consists of two main blocks, a comparator and a digital encoder. To reduce the metastability and the effect of bubble errors, the thermometer code is converted into the gray code and there after translated to binary code through encoder. The proposed encoder is thus implemented by using differential cascade voltage switch logic (DCVSL) to maintain high speed and low power dissipation. The proposed 5-bit flash ADC is designed using Cadence 180 nm CMOS technology with a supply rail voltage typically ±0.85 V. The simulation results include a total power dissipation of 46.69 mW, integral nonlinearity (INL) value of −0.30 LSB and differential nonlinearity (DNL) value of −0.24 LSB, of the flash ADC. Taninki Sai Lakshmi, Avireni Srinivasulu, and Pittala Chandra Shaker Copyright © 2014 Taninki Sai Lakshmi et al. All rights reserved. Analysis of the Coupling Coefficient in Inductive Energy Transfer Systems Tue, 17 Jun 2014 08:17:30 +0000 In wireless energy transfer systems, the energy is transferred from a power source to an electrical load without the need of physical connections. In this scope, inductive links have been widely studied as a way of implementing these systems. Although high efficiency can be achieved when the system is operating in a static state, it can drastically decrease if changes in the relative position and in the coupling coefficient between the coils occur. In this paper, we analyze the coupling coefficient as a function of the distance between two planar and coaxial coils in wireless energy transfer systems. A simple equation is derived from Neumann’s equation for mutual inductance, which is then used to calculate the coupling coefficient. The coupling coefficient is computed using CST Microwave Studio and compared to calculation and experimental results for two coils with an excitation signal of up to 10 MHz. The results showed that the equation presents good accuracy for geometric parameters that do not lead the solution of the elliptic integral of the first kind to infinity. Rafael Mendes Duarte and Gordana Klaric Felic Copyright © 2014 Rafael Mendes Duarte and Gordana Klaric Felic. All rights reserved. Y-Function Analysis of the Low Temperature Behavior of Ultrathin Film FD SOI MOSFETs Wed, 11 Jun 2014 11:16:35 +0000 The respective transfer characteristics of the ultrathin body (UTB) and gate recessed channel (GRC) device, sharing same W/L ratio but having a channel thickness of 46 nm, and 2.2 nm respectively, were measured at 300 K and at 77 K. By decreasing the temperature we found that the electrical behaviors of these devices were radically opposite: if for UTB device, the conductivity was increased, the opposite effect was observed for GRC. The low field electron mobility and series resistance values were extracted using a method based on Y-function for both the temperatures. If low values were found for UTB, very high values (>1) were extracted for GRC. Surprisingly, for the last device, the effective field mobility is found very low (<1) and is decreasing by lowering the temperature. After having discussed the limits of this analysis.This case study illustrates the advantage of the Y-analysis in discriminating a parameter of great relevance for nanoscale devices and gives a coherent interpretation of an anomalous electrical behavior. A. Karsenty and A. Chelly Copyright © 2014 A. Karsenty and A. Chelly. All rights reserved. A Novel Power Electronic Inverter Circuit for Transformerless Photovoltaic Systems Mon, 26 May 2014 07:26:41 +0000 Capacitive leakage current is one of the most important issues for transformerless photovoltaic systems. In order to deal with the capacitive leakage current, a new power electronic inverter circuit is proposed in this paper. The inverter circuit consists of six switches and operates with constant common mode voltage. Theoretical analysis is conducted to clarify the circuit operation principle and the common mode characteristic. The performance evaluation test is carried out, and test results demonstrate that the capacitive leakage current can be significantly minimized with the proposed power electronic inverter circuit. Cao Hai-Yan Copyright © 2014 Cao Hai-Yan. All rights reserved. Active Comb Filter Using Operational Transconductance Amplifier Thu, 22 May 2014 10:52:37 +0000 A new approach for the design of an active comb filter is proposed to remove the selected frequencies of various signals. The proposed filter is based on only OTAs and capacitors, hence suitable for monolithic integrated circuit implementation. The workability of the circuit is tested using PSPICE for test signals of 60, 180, 300, and 420 Hz as in ECG signal. The results are given in the paper and found to agree well with theory. Rajeev Kumar Ranjan, Surya Prasanna Yalla, Shubham Sorya, and Sajal K. Paul Copyright © 2014 Rajeev Kumar Ranjan et al. All rights reserved. Design of a 2 GHz Linear-in-dB Variable-Gain Amplifier with 80-dB Gain Range Thu, 17 Apr 2014 12:03:58 +0000 A broadband linear-in-dB variable-gain amplifier (VGA) circuit is implemented in 0.18 μm SiGe BiCMOS process. The VGA comprises two cascaded variable-gain core, in which a hybrid current-steering current gain cell is inserted in the Cherry-Hooper amplifier to maintain a broad bandwidth while covering a wide gain range. Postlayout simulation results confirm that the proposed circuit achieves a 2 GHz 3-dB bandwidth with wide linear-in-dB gain tuning range from −19 dB up to 61 dB. The amplifier offers a competitive gain bandwidth product of 2805 GHz at the maximum gain for a 110-GHz ft BiCMOS technology. The amplifier core consumes 31 mW from a 3.3 V supply and occupies active area of 280 μm by 140 μm. Zhengyu Sun and Yuepeng Yan Copyright © 2014 Zhengyu Sun and Yuepeng Yan. All rights reserved. Harmonic-Rejection Compact Bandpass Filter Using Defected Ground Structure for GPS Application Thu, 03 Apr 2014 08:17:23 +0000 A miniaturized bandpass filter (BPF) using defected ground structure (DGS) resonator with the characteristic of harmonic rejection is developed in this paper. The second and third harmonics of the proposed BPF are rejected by the characteristic of stepped-impedance DGS resonator. Moreover, open stubs are established so that two adjustable transmission zeros can independently be created to extend the stopband and improve the rejection level. Finally, a second-order BPF, centered at 1.62 GHz with a stopband extended up to 5.6 GHz and a rejection level better than 20 dB, is designed and implemented for GPS application. A good agreement between simulation and measurement verifies the validity of this design methodology. Haiwen Liu, Baoping Ren, Xiang Xiao, Zhichong Zhang, Shen Li, and Suping Peng Copyright © 2014 Haiwen Liu et al. All rights reserved.